Flying shortens the lives of bees, and worker honey bees will fly to find flowers whenever the weather is right, regardless of how much honey is already in the hive. Using climate and bee population models, researchers found that increasingly long autumns with good flying weather for bees raises the likelihood of colony collapse in the spring.

The study, published in Scientific Reports, focused on the Pacific Northwest but holds implications for hives across the U.S. The researchers also modeled a promising mitigation: putting colonies into indoor cold storage, so honey bees will cluster in their hive before too many workers wear out.

"This is a case where a small amount of warming, even in the near future, will make a big impact on honey bees," said lead author Kirti Rajagopalan, a Washington State University climate researcher. "It's not like this is something that can be expected 80 years from now. It is a more immediate impact that needs to be planned for."

For this study, researchers ran simulations through a honey bee population dynamics model using climate projections for 2050 and the end of the century at 2100. They found that honey bee colonies that spend the winter outside in many areas of the Pacific Northwest would likely experience spring colony collapses in both the near- and long-term scenarios. This also occurred under a simulation where climate change continued as it is progressing now and one where greenhouse gas emissions were reduced in the near future.